The Guardian (USA)

Ten years of the sun in one hour – Nasa releases mesmerisin­g space film

- Elias Visontay

Nasa has released a mesmerisin­g timelapse video of the sun that condenses an entire solar cycle into an hour of footage, using images of the star taken every hour continuous­ly over a decade.

Nasa’s Solar Dynamics Observator­y has gathered 425 million high-resolution images of the sun, from its launch in February 2010 until June this year, which have now been stitched together to form the video.

While the 20 million gigabytes of picture data captured over the decade have contribute­d to “countless new discoverie­s about the workings” of the sun, according to Nasa, the images have now been arranged into a 61-minute video showing events including transiting planets and eruptions.

The film shows the major changes the sun undergoes during a solar cycle, an approximat­ely 11-year period which sees the sun’s north and south poles flip, and the emergence of sunspots as a result of gas altering the star’s magnetic fields.

Every second of the 61-minute video represents images taken over a single day, with the first frame showing the sun on 2 June 2010, and the last frame captured on 1 June 2020.

With what Nasa describes as a “triad of instrument­s”, the SDO took a picture of the sun every 0.75 seconds on average, including the Atmospheri­c Imaging

Assembly instrument that captured images “every 12 seconds at 10 different wavelength­s of light”.

However, not every image the SDO has taken has been used in the timelapse video. Only images taken at one wavelength, 17.1 nanometres, were used in the video, with the extreme ultraviole­t wavelength of the images allowing for the sun’s golden yellow, outermost atmospheri­c layer – the corona – to be visible.

Nasa commission­ed German musician Lars Leonhard to compose Solar Observe to accompany the video.

In a statement released with the video, Nasa explained why there were a few blank frames in the video and the infrequent changes of focus away from the sun.

“While SDO has kept an unblinking eye pointed toward the sun, there have been a few moments it missed,” it said. “The dark frames in the video are caused by Earth or the moon eclipsing SDO as they pass between the spacecraft and the sun.”

Nasa also explained that a “longer blackout” in the footage in 2016 was caused by a temporary AIA instrument issue that took a week to fix.

“The images where the Sun is offcentre were observed when SDO was calibratin­g its instrument­s,” Nasa said.

The SDO mission is expected to continue observing the sun until 2030.

 ??  ?? A shot from Nasa’s video, which shows the major changes the sun undergoes during a solar cycle, an approximat­ely 11-year period which sees the sun’s north and south poles flip. Photograph: Nasa
A shot from Nasa’s video, which shows the major changes the sun undergoes during a solar cycle, an approximat­ely 11-year period which sees the sun’s north and south poles flip. Photograph: Nasa

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